1. Field of the Invention
The invention relates generally to the field of measurement of relative liquid percentages, and more particularly to measurement of the proportion of oil in water.
2. Description of the Prior Art
In the prior art, various devices are extant which address the oil-in-water measurement problem. These are either chemical, mechanical, or optical, a general class into which the present invention falls. Among these prior art devices are those which basically measure conductivity or some other electrical parameter or the actual density of the mixture. Many of these known techniques are cumbersome, time consuming or unduly sensitive to the presence of other soluble or insoluble materials. In ocean water measurements, where the need for instrumentation of the type is the greatest, the relative salinity is an interfering variable. Salinity can vary considerably between open ocean on the one hand, and estuaries and sheltered sea areas on the other hand. Certain prior art instruments for the same measurement purpose rely on ultra-violet fluorescence or infra-red absorption change as a result of oil content. Those provide relatively rapid determinations, but are sensitive to salinity changes necessitating frequent calibration when used on shipboard.